Urinary cytokeratin 20 (encode by Krt20) as a predictor for chronic kidney disease following acute kidney injury

Kidney transcriptome sequencing was applied to identify the top up-regulated genes in mice with AKI. The product of the top-ranked gene was identified in the tubular cells and urine both in mouse and human AKI. Data from two cohorts of patients with a prehospitalization estimated glomerular filtration rate (eGFR) ≥ 45ml/min/1.73m2 who survived for at least 90 days after AKI were used to derive and validate multivariable prediction models. AKI to CKD progression was defined as a persistent eGFR < 60ml/min/1.73m2 and with a minimum 25% reduction from baseline eGFR 90 days after AKI in patients with prehospitalization eGFR ≥ 60ml/min/1.73m2. AKI to advanced CKD was defined by a sustained reduction of eGFR < 30 ml/min/1.73m2 90 days after AKI in those with prehospitalization eGFR 45-60ml/min/1.73m2. Kidney cytokeratin 20 (CK20) was significantly up-regulated in injured proximal tubular cells and detectable in urine within 7 days after AKI. High concentrations of urinary CK20 (uCK20) were independently associated with the severity of histological AKI and the risk of AKI to CKD or advanced CKD progression. In Test set, the AUC of uCK20 for predicting AKI to CKD or advanced CKD was 0.80, outperformed currently used biomarkers for detecting kidney tubular injury. Addition of uCK20 to an established clinical model significantly improved the ability for predicting AKI-CKD progression with an AUC of 0.90, and largely improved the risk reclassification.In conclusion This finding highlighted uCK20 as a novel and useful predictor for AKI-CKD progression, and may provide a tool to early identify patients at high risk of CKD following AKI. Male C57BL/6 mice aged 6-8 weeks (20-24g) were purchased from Beijing SpePharm Biotechnology Co. Ltd. IRI was induced by clamping the left renal pedicle for 20-min (mild AKI) or 40-min (severe AKI) by using the microaneurysm clamps, genetic change between 20-min IRI (left kidney) and self-control kidneys (right kidney) or between 40-min IRI and self-control kidneys at 1d and 3d after AKI were analyzed. n = 6 for each group of mice. Overall, we used RNA sequencing to identify the top up-regulated genes in the kidney of mice with tubular epithelial cell injury.